Integrated circuits include combinations of electroactive devices such as resistors, diodes, capacitors and transistors linked together by electrical connections. Thin film integrated circuits include a number of layers such as metal layers, dielectric layers, and active layers typically formed on a semiconductor material. Typically, thin film circuit elements and thin film integrated circuits are created by depositing various layers of material and then patterning the layers using photolithography in an additive or a subtractive process which can include a chemical etching step to define various circuit components.
Traditional integrated circuits can be built directly on a silicon chip. More recently, there has been an interest in flexible integrated circuits. It has been shown that semiconductors such as zinc oxide can be deposited on glass or plastic substrates that can then be used to build very useful integrated circuits. The current method used for patterning most layers in thin film integrated circuits, such as those found in flat panel displays, is to deposit a continuous layer of a given material (such as a semiconductor for thin film transistors), coat the layer with a photoresist, pattern the photoresist by exposure to radiation, develop the photoresist, and then etch away the unprotected parts of the continuous layer using either a dry or wet etching process to produce the patterned circuit element.